PROJECT SUMMARY An important question in developmental biology is how cell fate specification and cell movement are coordinated during tissue morphogenesis to ensure all cell types reach their desired positions properly. One example of this elegant coordination is the patterning of neural progenitors in the zebrafish spinal cord. In this proposal, I will combine biophysical and genetic approaches to understand how cell fate specification and cell adhesion are coordinated in the zebrafish neural tube. Studies from my early postdoctoral training have identified E-cadherin (Cdh1), N-cadherin (Cdh2), and their transcriptional regulators as critical mediators for patterning of neural progenitor domains. Building on these initial findings, this proposal aims to obtain a multi- scale understanding of spinal cord pattern formation from the differential adhesion forces mediated by Cdh1 and Cdh2 in different neural progenitor cell types (Aim1), to the gene regulatory network controlling the spatial patterns of Cdh1 and Cdh2 expressions (Aim2), to a computational framework to simulate cell sorting at the tissue scale (Aim1). The experimental platform established in Aims 1 and 2 will be used to characterize novel regulators of cell adhesion dynamics during spinal cord pattern formation and morphogenesis (Aim 3). This proposal will combine my analytical skills developed as a graduate student to analyze spatiotemporal dynamics of adhesion molecules at cellular and subcellular levels, the experimental knowledge acquired during my early postdoctoral training to genetically engineer zebrafish and image live embryos with single cell resolution, and the proposed training during the K99 mentored phase to probe cell mechanics and optically perturb gene expression at high spatiotemporal precision. The training during the K99 mentored phase will integrate the expertise of all four of my co-mentors and will complement my past training to form a complete research program in my own independent lab to measure, perturb, and model spatiotemporal dynamics of adhesion molecules in neural progenitor cells during spinal cord development. My plan for transitioning to independence include professional trainings from all four of my co-mentors to mentor students, manage labs, write grants, publish papers, present research results in conferences, and establish scientific collaborations. By learning and interacting with all four co-mentors in different academic institutes, I will combine their strength to formulate my own lab culture and mentoring style. My long-term career goal is to direct a multidisciplinary research program studying the control of spatiotemporal dynamics of cellular and subcellular events underlying robust embryo development. So far I have achieved significant progress towards this goal in the form of research experience, successful publications, and initiation of collaborations. I firmly believe, however, that a K99 mentored phase will help maximize my chances for success by providing access to additional mentorship and training that would be otherwise lacking from my current postdoctoral experience.